The field of this invention relates to a pump, and more particularly to a blood infusion pump which is designed to be employed in combination with a blood bag for the purpose of causing a metered discharge of blood.
It is common knowledge that when a transfusion is being given to a human being, it is necessary to locate the supply of blood a distance above the transfusion area so that gravity will cause the blood to be forced into the patient. This is a conventional blood infusion process. The primary disadvantage to this type of process is that there is no way to increase the flow of blood into the patient, as it is controlled by the force of gravity.
In recent years, hospitals have employed blood infusion pumps. Most blood infusion pumps are designed to be employed in combination with a blood bag. A blood bag is the conventional way in which blood is stored and then utilized. One common type of a blood infusion pump takes the form of a spring biased plate which is to press against the blood bag, and will thereupon create the sufficient pressure to push the blood out of the blood bag and into the patient. One problem with such a spring biased plate is that as the blood bag empties, the pressure diminishes. This lack of constant pressure inherently causes a variance of the rate of flow of blood into the patient. It is most desirable to have the rate of flow be constant so that the precise quantity of blood that is being given to the patient in a set period of time can be known. Also, blood can be given to a patient at a known maximum rate which can maximize the blood intake by the patient, which may be very desirable at certain times.
Additionally, other conventional blood infusion pumps are driven by electricity. However, if an electrical power outage occurs, the electrically operated blood infusion pump no longer is operable. At certain times, this could very create an extremely critical situation.
There is a need for a blood infusion pump which is operated in a manner to discharge blood at a precisely controlled, constant rate. Also, there is a need for a blood infusion pump wherein the rate of discharge of blood can be readily varied. Further, there is a need for a blood infusion pump which is operated independently of outside sources of energy.